1. Field of the Invention
The present invention relates to a cell assembling device and, more particularly, to the arbitration of the order of cell transmission to be effected when, e.g., a plurality of channels of speeches or data are sent in the form of ATM (Asynchronous Transfer Mode) cells.
2. Description of the Background Art
ATM communication apparatuses and ATM switches have recently been proposed in various forms. An ATM communication apparatus, for example, is constructed to receive a speech signal and transform it to cells having a fixed length, or to transform communication data input from a terminal unit to cells. The ATM communication apparatus may be constructed to receive a plurality of parallel speech signals or data alone and multiplex them into ATM cells. It has been customary with the apparatus of the type receiving parallel speech signals or data to fix the order of ATM cell transmission, to send assembled ATM cells in a preselected order.
When a plurality of channels of speech signals or data are sent in the form of channel-by-channel ATM cells, it is necessary to set up an optimal transmission order in conformity to the transmission rates of the individual speech signals (e.g., 64 kbps (kilobits per second), 32 kbps or 16 kbps) or the data. Further, every time the bit rate or the data rate is changed, the optimal transmission order must be changed.
Moreover, when the configuration is noticeably different from one channel to another channel, it is likely that the required capacity of an ATM cell assemblage buffer increases or that the buffer overflows and causes data to be discarded, depending on the transmission order.